<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Tue, Nov 4, 2025 at 4:46\u202fPM Andreas Dilger <<a href="mailto:adilger@dilger.ca">adilger@dilger.ca</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Nov 4, 2025, at 5:28 PM, Jinshan Xiong <<a href="mailto:jinshanx@google.com" target="_blank">jinshanx@google.com</a>> wrote:<br>
> On Tue, Nov 4, 2025 at 4:20\u202fPM Andreas Dilger wrote:<br>
>> I don't see how the layout xattr format is related to filesystem-level<br>
>> scanning? This is "just" the xattr format *STORED ON THE OST OBJECT*,<br>
>> and it could be handled by direct device-level (OST) scan tools as well.<br>
> <br>
> I see. I initially thought you proposed the spill device would function as a mirror and that the existing software stack would handle it.<br>
> <br>
> Are we going to store the spilled object's status in the layout? It sounds difficult because you will have to initiate a layout change from the OSTs. I think we still need to store such an xattr locally in the OST object.<br>
<br>
I'm exactly proposing that the layout xattr be stored on the OST object.<br>
It would have the same format as the existing Lustre layout stored on<br>
the MDT, but *maybe* a different name (e.g. "trusted.spl", "trusted.osd",<br>
or whatever).<br>
<br>
I'm not sure if using "trusted.lov" will confuse filesystem scanning<br>
tools or help them... It probably makes sense to have a different<br>
xattr name, just in case we want MDT spilling (e.g. NVRAM->QLC) in<br>
the future.<br></blockquote><div><br></div><div>I would prefer a different name, even though the client likely won't see it directly. Using the same name for different things will only lead to confusion. I would go for "trusted.spl".</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
>> This would allow mirrors (FLR), multiple spill devices (multiple FLR<br>
>> mirrors), concatenated devices (PFL), etc. It just avoids adding new<br>
>> formats that need to be parsed, printed, etc.<br>
<br>
Cheers, Andreas<br>
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